1. Field of the Invention
This invention relates generally to the art of fluid filtration and more particularly to a novel fluid filter and filter cleaning method.
2. Discussion of the Prior Art
As will become evident from the ensuring description, the principles of this invention may be utilized in fluid filters for a wide variety of fluid filtration purposes. The invention, however, is particularly concerned with filtering swimming pool water and for this reason will be described, but without limitation, in the swimming pool context. In this regard, important advantages of the filter are ease of cleaning, simplicity of construction, low cost, elimination of particulate filter aid.
The reasons for filtering swimming pool water are well known and need not be treated in detail here. Suffice it to say that the water in swimming pools tends to accumulate foreign matter owing to the nature of swimming pool use, the normal outdoor location of swimming pools, and the inherent tendency of swimming pool water to support the growth of algae and bacteria. Typical examples of foreign matter which tend to accumulate in the water of swimming pools are dust, dirt, leaves, and the like; oils such as hair oils and suntan lotion; algae; gelatinous materials resulting from the interaction of chemicals of various sorts which are used to treat pool waters; and insoluable salt products resulting from the chemical reaction between the chlorine and other reactive materials employed to treat the water. For reasons of health, safety and appearance, it is essential to minimize such water pollutants. This is generally accomplished by mechanical filtration. Such mechanical filtration generally involves the passage of the swimming pool water through a filtering medium such as sand or a porous element coated with diatomaceous earth or other expendible filter aid.
The prior art is replete with a vast assortment of fluid filters for filtering swimming pool water and a wide variety of other fluid filtering applications. Examples of such filters are described in the following patents: U.S. Pat. Nos. 3,202,284 and 2,468,354.
While these and other existing filters are satisfactory to some degree, cleaning the filters always presents a problem. A major problem common to all swimming pool filters, for example, resides in the fact that the foreign matter entrained in the pool water passing through the filters tends to form a cake on the upstream surface of the filtering medium. This cake gradually increases in thickness and density, and, as a consequence, presents increasing resistance to water flow through the filter. Frequent servicing of the filters, as by backwashing, spinning the filter element, or otherwise removing the cake of foreign matter, is necessary to periodically restore the filters to their proper operating condition. In those filters which utilize a coating of diatomaceous earth or other filter aid on a porous filter element, periodic servicing of the filters also requires recoating of the element with fresh filter aid which tends to be somewhat difficult and costly. Other filter cleaning problems could be discussed, such as disposing of used filter aid. Suffice it to say, however, that there is a definite need for an improved, more easily and conveniently cleanable filter. The present invention provides such an improved filter.